/Engine/Plugins/Runtime/XRBase/Source/XRBase/Public/HeadMountedDisplayFunctionLibrary.h
Returns the current VR pixel density. Pixel density sets the VR render target texture size as a factor of recommended texture size. The recommended texture size is the size that will result in no under sampling in most distorted area of the view when computing the final image to be displayed on the device by the runtime compositor.
(float) The pixel density to be used in VR mode.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintPure, Category="Input|HeadMountedDisplay") static float GetPixelDensity()